cant change gamertag

I cant change my gamertag its so ANNOYING plz fix it soon in an update plz it isn't a big thing but its just that annoying little thing thanks so much mojang il be sure to rate 5 stars ive played it since I was 6 and I'm near 9 but higher now that's just for internet safty I learn in school well thanks so much and bye hopfully I wont report another thing